Lasers and waterjets open up whole new worlds of stone-cutting to the creative sign builder

By Charlie Fletcher
Reprinted with permission from Sign Builder Illustrated

Engraving and cutting in stone have come a long way since the times of the mallet, chisel, and saw. Today's computer technology has opened up lucrative new areas of business for sign makers, and when you add in the fact that prices for stone have fallen dramatically in recent years, you have the makings of a great new product line for your sign shop-making stone artwork for the commercial and residential markets.

Paul West, sales manager for Crone Monument, in Memphis, Tennessee, has
watched in wonder as his commercial and residential signmaking business has
gone from nearly nothing to about 25 percent of his business in about five
years with no active marketing. "I guess it went from monuments to civic
memorials, and then we'd done enough of this stuff that people started
getting to know us and contractors started coming looking for our work," he
says.

On the other hand, the architectural industry is waking up to stone, says
Mark Eisenwinter, administrative manager for Granite City Tool Company of
Barre, Vermont. "More and more commercial and residential projects are
using granite," he says. "The reason is that there's a lot of stone
imported from India and China on the market." The imported granite is so
cheap, in fact, that the price differential between the stone and tile or
Formica countertops Eisenwinter sells is nearly nonexistent. What's more,
imported granites have brought a rainbow of new colors into play for
designers-blacks, reds, and pinks that were rarely seen in the United
States until now.

Best of all, modern computers, lasers, waterjets, and CNC controls bring
into play a whole palette of new techniques that will not only allow you to
be more creative, but create finished art more cheaply than ever before. At
the foundation of any modern stone cutting operation is the computer. For
some work, it may be necessary to invest in a CAD program to work in three
dimensions, but many successful designers are simply producing their
artwork using programs such as CorelDraw, Adobe Illustrator, Photoshop, or
Macromedia FreeHand, all of which produce two-dimensional output.

You see, today's most advanced stone-cutting devices are really just fancy
printing devices for your computer. "I had a venture capitalist from
Silicon Valley here taking a look at my operation a while back," says Jim
Bellilove, CEO, president, and director of Creative Edge Corporation, of
Fairfield, Iowa. "This guy had been involved in a number of computer
company startups. He took a look at our waterjet system and how it was
running jobs off the computer and said, 'This is the most amazing output
device I've ever seen.'" Two stone-cutting tools stand out from the rest to
bring you the widest range of artistic capabilities: the laser engraver and
the abrasive waterjet. Neither tool is terribly new on the market. However,
with materials costs coming down and labor savings taken into account, both
are becoming logical choices for the craftsman who is serious about stone.

Laser engraving systems are excellent tools for etching small letters and
high-quality graphics onto black granite, says Scott Steckman, president of
Steckman Memorials. Steckman had been etching portraits onto granite for
many years using the services of a staff artist who did the work by hand.
"We'd had a lot of problems with the artist's interpretation. Sometimes
people didn't think the etchings looked like the people they were supposed
to represent," he says. "Also, the cost of having an artist do that is high
in comparison to the cost of doing it with a laser." Steckman now etches
digitized artwork, photographs, drawings, whatever the job calls for right
onto the stone. The art can be etched at resolutions as high as 1,200 dots
per inch in 256 shades of gray. It's literally photo-realistic art printed
on stone.

Steckman finds the laser engraver particularly useful for etching small
type sizes onto stone. Although he still uses sandblasting for most of the
lettering he engraves, when it comes to letters less than 1/4-inch high,
Steckman goes to the laser. In fact, the laser engraver can successfully
etch legible letters onto stone at sizes ranging down to 1/16-inch in
height. Because the system is computerized, you can set your type in any
font you desire. Most laser engraving systems use carbon-dioxide lasers at
a wattage between 10 watts and 100 watts. However, the best results for
etching granite are achieved with 25-watt or 50-watt systems, according to
Josh Siegel, sales and marketing director for Vinyl Technologies, Inc., of
Littleton, Massachusetts. The company markets a line of laser engravers
under the VyTek brand that are especially designed for large-format work,
such as stone engraving. "We find that we get the best results with the
laser when it's operating at full power," Siegel says. "If you're operating
the machine at, say, 25 percent of full power, we've found that you won't
get a high-quality beam. Since you only need 25 watts to 50 watts to etch
stone, we recommend that power for our engraving systems."

Laser can cut quite deeply into stone, if the design calls for it, says
Siegel. Although it is also possible to cut completely through stone with a
laser engraver, because the beam can only cut about 1/8 of an inch deep on
each pass, it's really not practical for stone cutting. The reason is
simple: the process would take too long. The laser systems can also be used
to engrave artwork onto urns and other rounded surfaces with the use of a
special rotary engraving attachment. The rotary attachment takes over one
axis of the machine's two-axis controls, rotating the work as needed to
keep it properly positioned under the laser beam. Lasers are good for
cutting all sorts of hard materials, not just granite. You can also use a
laser to cut marble and ceramic tile. But don't try to cut glass or metal;
both will produce disastrous results and can even damage the laser.

Laser engraving systems come in a wide variety of configurations to
accommodate jobs both small and large. Slabs as large as 4 feet by 8 feet
and larger can be successfully handled without difficulty. Large-format
lasers usually come either with a stationary table and a gantry-mounted
laser, or with movable table. Some systems also use conveyor belts. Prices
for large-format laser engraving systems are about $70,000 for an average
system.

If you're interested in cutting completely through a piece of stone, your
best bet is the CNC abrasive waterjet. Although there are several other
tools on the market today that will do precision stone-cutting, for highly
detailed artwork the waterjet offers some significant advantages: It
doesn't heat the material being cut, it doesn't vibrate the material, and
it doesn't require a starting hole. For Jim Bellilove of Creative Edge, it
was love at first sight when he saw a waterjet. "We got involved with the
waterjet first, and then we found a market," he says. "Our basic business
concept is organized around the machine."

Creative Edge is actually two businesses in one. Bellilove operates both
in the artistic realm, serving the needs of the architectural-design
market, and in the industrial realm, using his machines to do industrial
cutting. He has expertise in executing complex inlays that combine a
variety of materials, such as stone, tile, and metals. "This kind of
equipment is the best breakthrough in stone-cutting in hundreds of years,"
Bellilove says. "Any shape can be cut as long as the material is flat. Any
material can be combined with stone. The technology just by itself creates
a whole range of design possibilities." The waterjet works by shooting out
a fine stream of water at high speed. However, when you're cutting through
stone, water alone is not enough. You'll also need an abrasive. The most
common one used with the waterjet is garnet.

Surprisingly little water is used by the waterjet itself . It only uses
about a gallon a minute that is sprayed out of its tiny nozzle in a stream
going about3,000 feet per minute, with about 50,000 PSI of pressure behind
it. The waterjet stream used to cut stone is generally in the range of
0.003 inch. Since the kerf is extremely small and the material surrounding
the cut doesn't heat up and warp, there is very little wasted material in a
waterjet operation. In addition, the waterjet doesn't need a pilot hole to
get started on an interior cut. It pierces right through the material
wherever it begins, without leaving perceptible evidence of where the cut
started. In order to use the waterjet and your computer together, you will,
of course, need to use a CNC motion system. This handy little bit of
hardware interprets the computer's digital instructions during the printing
process and makes the waterjet act like a stencil-cutting machine.

The advantages of using a CNC abrasive waterjet for precision stone cutting
are many. It can cut the time necessary to produce complex stone cutting
from weeks to hours. Because the waterjet doesn't heat up the stone or
vibrate it, the resulting cut pieces are free of cracks and cut to a
precision of +/- 0.005 inch. A waterjet is best used to make cuts
completely through the material on which it is working-and it can cut
through stone up to 8 inches thick.

However, some operators are using the waterjet for specialized engraving.
Brandon Gates, production manager for Precision H2O of Spokane, Washington,
says he regularly uses the waterjet to etch complex designs on stone.
"We've etched with no problem and gotten some beautiful results," says
Gates. To cut a groove in stone, instead of going completely through, Gates
increases the head speed, decreases the water pressure, and decreases the
garnet flow. Because the bottoms of the grooves aren't a consistent depth,
Gates fills them in with grout, leaving behind an attractive precision
etching in a contrasting color.

Waterjet systems come in a variety of configurations. Typically prices
begin at about $100,000 for a basic CNC system. Although the waterjet only
uses about a gallon per minute for the actual cutting, it uses another 5 to
7 gallons per minute to cool the pressure intensifier pump. While water
consumption is not excessive, and there are no blades or bits to wear out,
there is still a fair amount of maintenance that must be regularly
performed. Says Bellilove, "There are a whole bunch of components in the
system, which, because of the high water pressures, wear out quickly." High
pressure takes its toll on the waterjet's hoses and gaskets. The garnet
abrasive, an expensive supply in and of itself, causes the waterjet nozzles
to wear out quickly, as well.

Yet, in spite of these shortcomings, the waterjet's advantages are still
weighty, and designs that could only be accomplished using one are
increasing in popularity. "It's a moderately challenging technology,"
Bellilove says. "But architects, interior designers, and graphic designers
are only just realizing that they have these options."